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The equivalent of a strong cup of coffee a day could act as an effective memory-enhancer say scientists. [Photo: Bigstock]

Caffeine could help enhance long-term memory

Natural Health News — The consumption of caffeine is the energy boost of choice for millions to wake up or stay up. Now, however, researchers  have found another use for the stimulant: memory enhancer.

Writing in the journal Nature Neuroscience, researchers at Johns Hopkins University led by Michael Yassa, assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences have shown that caffeine can help enhance long-term memory.

“We’ve always known that caffeine has cognitive-enhancing effects, but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans,” said Yassa. “We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours.”

In their double-blind trial participants who did not regularly eat or drink caffeinated products were given either a placebo or a 200-milligram caffeine tablet (or roughly one strong cup of coffee or two small cups of coffee) five minutes after studying a series of images. Salivary samples were taken from the participants before they took the tablets to measure their caffeine levels. Samples were taken again one, three and 24 hours afterwards.

The next day, both groups were given a complex test to judge their ability to recognise images from the previous day’s study session. On the test, some of the visuals were the same as from the day before, some were new additions and some were similar but not the same as the items previously viewed. More members of the caffeine group were able to correctly identify the new images as “similar” to previously viewed images versus erroneously citing them as the same.

The brain’s ability to recognize the difference between two similar but not identical items, called pattern separation, reflects a deeper level of memory retention, the researchers said.

A different part of the brain

“If we used a standard recognition memory task without these tricky similar items, we would have found no effect of caffeine,” Yassa said. “However, using these items requires the brain to make a more difficult discrimination – what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case.”

The memory centre in the human brain is the hippocampus, a seahorse-shaped area in the medial temporal lobe of the brain. The hippocampus is the switchbox for all short-term and long-term memories. Most research done on memory – from the effects of concussions in athletics to war-related head injuries to dementia in the ageing population – are focused on this area of the brain.

Until now, caffeine’s effects on long-term memory had not been examined in detail. Of the few studies done, the general consensus was that caffeine has little or no effect on long-term memory retention.

But still not a definitive answer

The research is different from prior experiments because the subjects took the caffeine tablets only after they had viewed and attempted to memorise the images.

“Almost all prior studies administered caffeine before the study session, so if there is an enhancement, it’s not clear if it’s due to caffeine’s effects on attention, vigilance, focus or other factors. By administering caffeine after the experiment, we rule out all of these effects and make sure that if there is an enhancement, it’s due to memory and nothing else,” said Yassa.

“The next step for us is to figure out the brain mechanisms underlying this enhancement,” he said. “We can use brain-imaging techniques to address these questions. We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer’s disease. These are certainly important questions for the future.”

• For more on the pros and cons of caffeine consumption see our feature Caffeine – angel or devil?